Erik ollestad



UNTTED STATES ATENT OFFICE;

ERIK OLL lSTA'D, OF ST. PAUL, MINNESOTA, ASSIGNOR OF ONE-HALF TO ANDREIV.IENSON, OF SAME PLACE.

TANNING PROCESS.

SPECIFICATION forming part of Letters Patent No. 401,? 15, dated April16, 1889.

Application filed March 2, 1888. Serial No. 265,955. (No specimens.)

T0 aZZ whom it may concern:

Be it known that 1, ERIK OLLESTAD, a citizen of Norway, residing at St.Paul, in the county of Ramsey and State of Minnesota, have inventedcertain new and u seful Impro vementsin the Process of Tanning Hides;and I do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilledin theart to Which it appertains to make and use the same.

This invention relates to an improved process of tanning; and it has forits object the production of a softer and finer leather and stronger inmuch shorter time than hereto fore, as will be more fully hereinafterdescribed, and then specifically defined by the claim.

The ordinary method of tanning by the use of bark has one objection-thatof consuming too long a time in the process of tanning. Certainchemicals have been used of late which have considerably shortened thetime of tanning; but those that have been used heretofore have not beenentirely successful in producing as good results as from the old methodof bark-tanning. In my method I not only accomplish as good results asfrom the bark process, but make leather a great deal stronger and morewater-proof, as well as softer and more pliable. I make use of bothchemicals and extracts. By extracts Iwish to be understood as coveringany extracts that may be used for the purpose of tanning-such as theextract of hemlock-bark, the extract of oak-bark, japonica, &c. I usethe extracts also for the reason that by using both chemicals andextracts the leather by being tanned in this way obtains the sameproperties as leather tanned in the ordinary bark process, which fact isof great importance to the subsequent preparation in dyeing cf theleather. The chemicals I make use of are blue vitriol, bichromate ofpotash, al um. and sulphuric acid. Soaking, fleshing, and the removingof hair are done in the usual way. Large hides for belting or for otherpurposes where unusual strength is required are taken after the hair andflesh have been removed and placed as they are in the liquor.

The proportions of the ingredients used are as follows: In tanning tenordinary hides I been thoroughly dissolved I take one-fourth part of thesame and put in a vat, together with the necessary water, which is thenpoured into the stufiing-wheel. This liquor is then heated to atemperature of from to Fahrenheit, after which the hides are placed inthe liquor, and the stuffing-wheel is kept turning around about one hourat a time three times per day. The third day the hides are taken out andanother one-fourth part of the above-named solution is added to theliquor in the stuffing-wheel, which is then heated to a temperature of30. The hides are again placed in the stufling-wheel, which is keptturning around at intervals, as before, until it is apparent that theliquor has lost its strength, when thehides are again taken out, and theremaining one-half of the solution is added to the liquor in thestuffingwheel, which is also heated to a temperature of 30, and afterthe hides have been replaced therein it is kept turning around atintervals, as before, until in the course of about fourteen days thehides will be tanned. In the washing of the leather I make use ofordinary lye extracted from maple-wood ashes and rub it well with goodboiled trainoil on the grain or hair side, and with threefourths parttrain-oil and one-fourth part of rosin, which is boiled together, on theflesh side. The leather is now rubbed well with the above-namedmixtures, according to its thickness, and hung up until about one-halfdried, when it is taken down and stretched and hung up again untilentirely dried. It is then taken down, rolled, and finished.

In tanning skins or upper-leather, kid, &c., allimpurities must first beremoved, which is done in the ordinary way. I now make use of muriaticacid (the quantity being small, just sufficient to continue to make thetannic liquid sour) instead of sulphuric acid.

The time absorbed in tanning, on account of the skins being lighter, isalso reduced from two to eight days. After the skins are tanned andtaken out of the liquor they'are thoroughly rinsed and washed in lye.They are then rubbed with a boiled mixture of trainoil and tallow andhung up until about oneha'lf dry, when they are taken down and theabove-11 amed mixture thoroughly worked into the skins and again hung upuntil entirely dry. The skins are now placed in lye that is heated to atemperature of 25, and all the grease is then washed out until they areentirely clean. They are then stretched and smoothed and again hung upto dry, after which they are ready for dyeing.

Importance is attached to the use of the blue vitriol and bichromate ofpotash, as

